Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1887-06-11
VITICULTURAL.
INVESTIGATIONS AT THE UNIyER.
SHY EXPERIMENT STATION.
Concerning the Abnormal Deposits
on Grape Leaves and Consequent
Death of Vines-Remedies

On Ofap Pc Leaves ana CONSEQUENT
Death of Vines-Remedies.
The following bulletin has been issued
from the Agricultural Experiment Station
of the University OF California at Berke-
ley, and will be of interest to all vine
growers of the State:
On May l4th few leaves from a Mus
cat vine were received from +. II. Love
/ land, foreman of the Butler vineyard at
Fresno. Mr.. Lovelands attention had
! been attracted by what seemed to be ii
growth OF fungus on the leaves and on one
side of the trunk of the vine He wrote
I that he had noticed the same thing before.
but never IN such amount as this season.
! A preliminary examination of the speci-
mems showed that the leaves. though ap-
pearing quite healthy in color, were
thickly covered on both sides with a
whltish substance occurring in irregular
masses, and which at first glance might
give some suspicion of flngoid growth.
Examined with a hand-maguifier, how
ever, the material was seen to be of dense
character, and prone to lift from the sur
fact, IN some places, especially where it
had extended over the ribs of the leaf il
had divided and partly lifted itself from
the surface, as though it had become
shrunken and distorted by drying. No
features of fungoid growth were diseer-
nlble. Upon careful exploration with
three-fourth inch objective the marks
shown by the Kindergarten were made
more plain, and the whitish masses gave
indications of a crystalline structure,
maniiesting itself in two main forms. The
thinner portions were chiefly made up of
tiattish crystallizations of aborescent form.
spreading out upon the surface of the leaf,
and the thicker parts were dense white
masses covered thickly with acicular crys-
tails. The whole appearance OF the ma
terIal was that of an incrustation held in
place by adhesion and by Interviewing of
the leaf hairs through it, the latter fact
indicating that it had come upon the leaf
in fluid state and had thus taken close
hold upon the inequalities of the leaf
surface. This being the character of the
deposit as being determined by the micro
scope, and as no traces of fungoid origin
could be discerned, it was evident that the
composition of the material, as determined
by chemical examination, would be most
apt TO disclose its source.
The small amount Of material which
could be scraped from the leaves, some
what less than one grain, rendered it i'm
possible to come to perfectly definite con-
illusions regarding its exact nature. The
original material contained: AS per cent.
insoluble in water, and 557 per cent solu-
Gle in water. OF the soluble part: COS
per cent. was organic matter and water, -
per cent. was soluble ash, and % O per cent.
was insoluble The part insoluble in water
contained: Sl.l per cent. of organic mat
ter and loss, and 1873 per cent. of ash.
The part of the original material in
soluble in water consists mostly of lime.
with small amount of magnesia and sui
phuric acid. A slight residue resembling
mica probably from the dust of the soi)
remains after the treatment with acid.
Sulphur Is present in sufficient quantities
to he easily detected when ignited-doubt-
less from the sulphuring of the vines.
The soluble part of the original material
was slightly acid. On ignition it blackens,
and emits slight odor of burnt sugar.
The presence of little sugar is also shown
by the copper test. The soluble part of its
ash is strongly alkaline, and consists largely
of carbonate of potash with some sulphuric
acid.
The insoluble part of its ash consists
chiefly of lime with a small amount of
magnesia.
The general result. of this examination
would seem to be that the white substance
is saline incrustation of organic salts of
potash and lime. Such a deposit might
result from the evaporation Of vine sap it
self, but its deficiency in gum and sugar
and apparent absence of tartaric acid
Judging from the crystalline form of the
incrustation) renders this supposition un-
likely.
OTHER SPECIMENS.
Another specimen sent by j. S. Dore, of
Borden, Fresno county, had all the char
acteristic marks of the specimen from the
Butler vineyard, except that the material
was less abundant. A specimen from Hi
ram Hamilton, of Orange, Los Angeles
county, differs in some respects from the
Fresno samples. The deposit is much
thinner, and looks as though drops Of thin
whitewash had fallen upon the leaf and
spread out upon it. 1t is most abundant
upon or near the outer edges of the leaves.
Examined with the microscope, the de-
post does not show the neede-shaped
crystals as in the former cases, but has in
stead somewhat irregular, roundish masses,
sometimes contiguous, sometimes separated
enough to show the green color of the leaf
surface beneath them. There is, however.
no indication Of fungoid form or growth,
but rather of granular formation, presum-
ably an incrustation. The material was
not abundant enough to admit of chemical
examination.
4 specimen received from G.. F. Mer-
riam, Escondido, San Diego county, resem-
bles closely the one from Orange, Los An
geIes county. Mr. Merriam writes: You
will notice along the edges of the leaves
something white, as if limewater had been
thrown upon them" In this sample the
thicker line Of incruetation along what
seems to be the part where most of the
liquid would collect by gravitation is
noticeable feature
FURTHER INVESTIGATION NEEDED.
We make this preliminary statement
concerning the nature of these abnormal
deposits upon vine leaves, because of the
interest which has been awakened in them
in the locations where they have occurred.
and to allay fears which seem to prevail
that the peculiar appearances are due to
the presence of ''downy mildew" (Peroao-
q,ora raicota)-a disease of the vine which
is properly dreaded. The wide announce
ment which has been made of the evil oc-
casioned by this fungoid parasite, naturally
renders vine-growers alert to detect signs
of its encroachment. 1t may be stated
that the ''downy mildew" exhibits its
presence by marks wholly dissimilar to
the characteristics of the incrustation
which we have described above. 1t forms
conspicuous white patches" of fuzzy or
| downy character, as its common name in
dicates. These patches may he very small,
bur iheir soft ,rnnllu nnt,,rn is crs;l.. do